Linear oscillating pressurizing device

ABSTRACT

A linear oscillating pressurizing includes a main body having an air outlet end and an air outlet valve, two electromagnetic elements disposed in the main body, a piston element disposed between the two electromagnetic elements, which has an air inlet valve disposed thereon, and a control circuit to generate oscillating current pulses. By using a series of current pulses generated from the control circuit, one can magnetize the two electromagnetic elements to the same polarity. By changing the polarity of the electromagnetic element, the attractive force and the repulsive force exerted on the piston element doubles the magnetic force used for reciprocating the piston element. By further incorporating the reciprocating movement of the piston element with the air flow, a pressurizing device having a doubled pressurizing output is obtained.

BACKGROUND OF THE INVENTION

The present invention relates generally to a linear oscillating pressurizing device, and more particularly to a linear oscillating pressurizing device that employs a permanent magnetic piston and two electromagnetic element to drive a piston element having an air inlet performing a reciprocating movement via a series of oscillating current pulse generated from a digital control circuit, thereby completing a pressuring action by employing the reciprocating movement of the piston element.

Conventional pressuring devices, such as pumps, or hydraulic or air pressurizing device, add energy or pressure to air or liquid. In general, pumps can be divided into centrifugal pumps and reciprocating pumps. The centrifugal pumps employ rotating blades to perform pressurizing actions, which is suitable for systems of high flow volume, low viscosity and static pressure.

The aforementioned reciprocating pumps are widely used in low flow volume pumping device or system. In other words, this type of pump can not be used in devices that require high flow volume or high pressure. The reciprocating pumps include steam pump and power pump. The power pump uses the persistent rotation of a motor to drive a piston through a shaft to generate persistent reciprocating motion of the piston. By incorporating the displacement of the piston and the change of direction, a pressure difference is formed between inside and outside of the pump, resulting into opening and closing of a valve element so as to complete one cycle of pressure transfer. However, such shaft transmission structure can easily waste energy output from the motor, especially when changing the moving direction of the shaft. The presence of the shaft requires the pump to have a larger volume. Therefore, it is not suitable for products of small volume, such as a blood pressure meter, especially a wrist type blood pressure meter or a finger type blood pressure meter.

Till now, an oscillating linear motor/driver is primarily applied to an actuator or an oscillating pump. The most commonly seen oscillating drivers include electromagnetic force only drivers and hybrid drivers. The electromagnetic force only drivers are driven purely by electromagnetic force. By purely relying on the attractive force of the magnetic force, an armature that reacts to magnetic force is driven to reciprocate between two external electromagnetic elements.

BRIEF SUMMARY OF THE INVENTION

The present invention is to provide a linear oscillating pressurizing device that employs a piston element made of permanent magnet and two electromagnetic elements. A series of oscillating current pulse cycle generated from a control circuit can drive the piston element having an air inlet valve to perform reciprocating movement and the air inlet control during the reciprocating movement, so as to complete the pressurizing action.

The present invention is also to provide a linear oscillating pressurizing device that employs a control circuit to generate a series of current pulses to magnetize the two electromagnetic elements to have the same polarity and to change polarity in response to current pulse cycle. The simultaneous attractive and repulsive forces exerted on the piston element by the two electromagnetic elements double the pressurizing effect.

The present invention is yet also to provide a linear oscillating pressurizing device that employs a control circuit to generate a series of oscillating current pulse cycle to directly drive the piston element made of permanent magnet and the direction of magnetic forces of the two electromagnetic elements. The size of such a pressurizing device can largely be reduced and applicable to micro devices such as wrist or finger electronic blood pressure meters, or other pressurizing devices. In addition, the operation noise of the present invention is also very low.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a conventional reciprocating actuator of electromagnetic force only type.

FIG. 2 illustrates a conventional reciprocating actuator of hybrid type.

FIG. 3 is a sectional view of the linear oscillating pressurizing device, in accordance with one embodiment of the present invention.

FIG. 4 is a block diagram of a control circuit, in accordance with one embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating the pressurizing and air flow status, in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In order to better understanding the features and technical contents of the present invention, the present invention is hereinafter described in detail by incorporating with the accompanying drawings. However, the accompanying drawings are only for the convenience of illustration and description, no limitation is intended thereto.

Referring first to FIG. 3 and FIG. 4, a linear oscillating pressurizing device in accordance with one embodiment of the present invention is illustrated. As shown, the pressurizing device includes: a main body 1 to contain all necessary elements of the present invention; two electromagnetic elements 21, 22 disposed in the main body 1; a piston element 3 disposed between the two electromagnetic elements 21, 22; and a control circuit 4 (not shown) electrically coupling the two electromagnetic elements 21, 22 to control magnetic properties.

The main body 1 includes an air room 14 and an air chamber 15, thereby defining a hollow space for proper operation. An air outlet end 11 is formed on one end of the main body 1 to provide air (or liquid) output. The output of fluid is controlled by turning on and off of a outlet valve 12. An air inlet end 12 is formed on the other end of the main body 1 to provide air (or liquid) input.

The magnetic elements 21, 22 are periodically driven by current pulses from a digital control circuit to make the magnetic elements 21, 22 magnetized and change the magnetic properties thereof. The electromagnetic elements 21, 22 are disposed inside of the main body 1 (such as the upper and lower ends of FIG. 3). Air passages 91, 92 are formed corresponding to the holes 13, 10. The space between the two electromagnetic elements 21, 22 is substantially the reciprocating space of the piston element 3.

The piston element 3 is disposed between the two electromagnetic elements 21, 22, as shown in FIG. 3. The piston element 3 is made of a permanent magnet. In this manner, when the electromagnetic element 21, 22 are magnetically excited, the piston element 3 can be attractively and repulsively driven towards one direction. Next, when changing the magnetic properties of the electromagnetic elements 21, 22, which will be described in detail in the following, the piston element 3 is driven to move towards the other direction. By changing the magnetic properties of the electromagnetic elements 21, 22, the piston element 3 reciprocates and repeatedly guides external air into the air bag 36. It is appreciated that the present invention is not applicable only to the air bag 36, but applicable to other things that needs pressurization and pumping. A hole 31 is formed on the end surface of the piston element 3 to dispose an air inlet valve 30, thereby providing the piston element 3 to turn on and off of air (or fluid) inlet during the reciprocating movement.

As shown in FIG. 4, the control circuit 4 can be of a digital type. The output end of the control circuit 4 is connected to the two electromagnetic element 21, 22, so as to use the generated series of current pulse cycle to excite and change the polarity of the two electromagnetic elements 21, 22. In this particular embodiment, the control circuit 4 includes a power switch circuit 41 for switching the external direct current power source, such as a battery, to alternating current. In this manner, the alternating current power source then has positive and negative pulse cycles to generate magnetic properties of different sort. An oscillating circuit 42 is connected to the power switch circuit 4 for generating a series of positive and negative current pulse cycle according to the input current described above, so as to drive and control the electromagnetic element 21, 22 for generating magnetic excitation and polarity changes. One can also employ the capacitance and resistance of the oscillating circuit 42 to generate directly a series of positive and negative current pulse cycle of different frequencies, thereby directly controlling or change the pressurization speed.

FIG. 5 a to FIG. 5 c illustrate the pressurizing operation of the linear oscillating pressurizing device. Referring to FIG. 5 a, the piston element 3 is in its standby status before any reciprocation. Here, we assume that the piston element adjacent the electromagnetic element 21 is an S pole, while the other end is an N pole. Before the piston element 3 starts reciprocating, the piston element 3 is located more adjacent to the electromagnetic element 21, and the air inlet valve 30 and air outlet valve 12 are both closed. When the control circuit 4 feeds in one cycle of a half wave current pulse (e.g. positive half wave current pulse) to the two electromagnetic elements 21, 22, the two electromagnetic elements 21, 22 are both magnetically excited to have the same polarity (e.g. S pole). At the same time, the electromagnetic element 21 and the piston element 3 form a repulsive magnetic force F1 (S pole to S pole), while the electromagnetic element 22 and the piston element 3 form an attractive magnetic force F2 (S pole to N pole). Thus, one can derive a magnetic force double to that of the conventional reciprocating magnetic pump to drive the piston element 3 moving towards the magnetic element 22 (i.e. marked as an arrow M, as shown in FIG. 5 b). When the piston element 3 moves towards the magnetic element 22, the air pressure in the air chamber 15 is lower than the atmospheric pressure, while the air pressure outside of the air chamber 15 is equal to the atmospheric pressure, thereby forming a pressure difference therebetween. By employing such a pressure difference, the air flow (or fluid flow) enters into the air chamber 15 through the air inlet end 13 from outside. This air flow (or fluid flow) opens the air inlet valve 30 and closes the air outlet valve 12. This is because that pressure in the air room 14 is higher than that of the air chamber 15.

After completing the air flow or fluid flow input described above, the control circuit feeds in a negative half wave current pulse to the two magnetic elements 21, 22. The two magnetic elements 21, 22 are both excited to another polarity (e.g. N pole). Meanwhile, the electromagnetic element 22 and the piston element 3 form a repulsive magnetic force F3, while the electromagnetic element 21 and the piston element 3 form an attractive magnetic force F4. Thus, one can derive a magnetic force double to that of the conventional reciprocating magnetic pump to drive the piston element 3 moving towards the magnetic element 21 (i.e. marked as an arrow M, as shown in FIG. 5 c). When the piston element 3 moves towards the magnetic element 21, there is formed a pressure difference. That is, the air pressure in the air chamber 15 is higher than the atmospheric pressure, while the air pressure outside of the air chamber 15 is equal to the atmospheric pressure. In addition, the air pressure in the air room 14 is higher than the atmospheric pressure but smaller than that of the air chamber 15. This pressure difference causes an air flow (or fluid flow) from high pressure area to low pressure area. This air flow (or fluid flow) closes the air inlet valve 30 and opens the air outlet valve 12, as shown in FIG. 5 c. The pressurized air flow is thus input into the air bag 36 through the air valve 12.

The present invention includes the following features and advantages:

-   -   1. Since two electromagnetic elements incorporating with the         piston element made of permanent magnet can form an attractive         force at one end and a repulse force in the other end, the         driving force is doubled than the conventional pressurizing         device, which obtains a high pressure (or high flow volume)         pressurizing effect.     -   2. The pressurizing device including a main body,         electromagnetic elements and a piston element is driven by a         control circuit, which can further reduce the size of the         pressurizing device to be applicable to micro device.     -   3. The control circuit is independent of the pressurizing         operation. Therefore, a series of positive and negative current         pulse cycle of different frequencies can be generated directly         by adjusting the capacitance and resistance thereof, thereby         controlling the flow rate and the pressurizing speed.     -   4. The pressurizing device includes a main body, electromagnetic         elements and a piston element, which is driven by a control         circuit. Therefore the structure of the pressurizing device is         simplified and the manufacturing cost is reduced.     -   5. In contrast to the conventional motor control, the present         invention does not require the use of a brush motor. Therefore,         the present invention is quiet in operation.

Since, any person having ordinary skill in the art may readily find various equivalent alterations or modifications in light of the features as disclosed above, it is appreciated that the scope of the present invention is defined in the following claims. Therefore, all such equivalent alterations or modifications without departing from the subject matter as set forth in the following claims is considered within the spirit and scope of the present invention. 

1. A linear oscillating pressurizing device, comprising: a main body with fluid contained therein; two electromagnetic elements disposed in the main body; and a piston element made of permanent magnet, which is disposed between the two electromagnetic elements, comprising an air inlet valve; whereby the two magnetic elements are temporarily magnetized to drive the piston element so that the fluid is guided through the air inlet valve to be pressurized.
 2. The pressurizing device as recited in claim 1, further comprising an air outlet end and an air outlet valve disposed on one end of the main body, and an air inlet end disposed on the other end of the main body.
 3. The pressurizing device as recited in claim 2, wherein the air inlet valve is opened when the piston element is driven to move towards the air inlet end, while the air inlet valve of the piston element is closed when the piston element is driven to move towards the air outlet end.
 4. The pressurizing device as recited in claim 1, wherein the two magnetic elements are simultaneously magnetized to have the same magnetic polarity, thereby forming an attractive force to one end of the piston element and a repulsive force to the other end of the piston element.
 5. The pressurizing device as recited in claim 1, wherein the fluid is air.
 6. The pressurizing device as recited in claim 1, wherein the fluid is liquid.
 7. The pressurizing device as recited in claim 1, further comprising a control circuit electrically connecting the two electromagnetic element to magnetize the electromagnetic elements and to change polarity thereof, the control circuit including: a current switch circuit transforming an input current into alternating current; and an oscillating circuit to generate a series of positive and negative current pulse cycles.
 8. The pressurizing device as recited in claim 7, wherein a frequency of the positive and negative current pulse cycles is adjusted by tuning a resistance and a capacitance of the control circuit, thereby controlling a pressurizing speed.
 9. A linear oscillating pressurizing device, comprising: a main body; two magnetic elements disposed in the main body; a piston element disposed between the two magnetic elements; air inlet valve disposed on the piston element; and a control circuit electrically connecting the two electromagnetic element to magnetize the electromagnetic elements and to change polarity thereof; wherein the two magnetic elements are temporarily magnetized to drive the piston element.
 10. The pressurizing device as recited in claim 9, wherein the control circuit comprising: a current switch circuit transforming an input current into alternating current; and an oscillating circuit to generate a series of positive and negative current pulse cycles.
 11. The pressurizing device as recited in claim 10, wherein a frequency of the positive and negative current pulse cycles is adjusted by tuning a resistance and a capacitance of the control circuit, thereby controlling a pressurizing speed.
 12. The pressurizing device as recited in claim 9, wherein the two magnetic elements are simultaneously magnetized to have the same magnetic polarity, thereby forming an attractive force to one end of the piston element and a repulsive force to the other end of the piston element. 